Robert A. DeLeo began his third term as House speaker Wednesday by announcing that, following the Newtown, Conn., school massacre, he wants to bring together lawmakers and specialists to study the “dangerous intersection of guns and mental illness in schools and throughout society.”

“As we mourn the lives that fell there, we grapple with solutions,” DeLeo said. “While much of this hopefully will take place on the federal level, I ­believe that we must do whatever we can on the state level as well.”

The Winthrop Democrat said he had asked criminologist Jack McDevitt, associate dean at Northeastern University, to help lead the effort.

DeLeo’s comments were made in an address during the inaugural session of the House, which began after he was reelected, 128-29, to another two-year term as speaker. Senate President Therese Murray was also reelected.

The first day of the session began as the Probation Department scandal continues to cast a long shadow over Beacon Hill, where questions have been raised over whether some legislators may have benefited from the agency’s allegedly rigged hiring system.

Amid the pomp and circumstance traditionally associated with the inaugural session, Governor Deval Patrick swore the members in, saying, “I look forward to working with each and every one of you to do the people’s business.”

The speaker did not detail specific proposals to address gun violence in his address. The slaughter of 20 children and six adults at the Sandy Hook Elementary School last month shocked the nation.

DeLeo spoke in more detail about the state’s transportation financing problems, saying the state faces a financing gap of billions of dollars over the next 25 years to keep roads, bridges, and tunnels in good repair. The MBTA has an estimated operating deficit of $130 million in the current fiscal year, he said.

The speaker said he was “frustrated by the depth of the financial troubles within our transportation system.”

“The root causes, in most cases, predate the sitting governor and those in this chamber, going as far back to the financing of the Big Dig and before,” he said. “But it’s our job to fix problems, not to dwell on how we got there.”

DeLeo said the Legislature should follow several principles in addressing transportation funding problems: The state must consider all opportunities for efficiencies; the burden of paying for the system must be borne equitably by different ­regions of the state; and roads, bridges, and tunnels must be maintained in “good and safe condition.”

He also said he had heard from the business community about increasing unemployment insurance rates and that he would ask that the House once again vote to freeze the rates and ask members to study ways to reform the system.

Reviewing the past session, he praised passage of laws to contain health care costs, change the way municipal workers purchase health insurance, and boost the economy.

DeLeo’s reelection came in a roll call that concluded about 12:30 p.m., after each member called out their pick for the post. Bradley Jones Jr., leader of the body’s vastly outnumbered Republicans, was the second-place finisher.

When DeLeo’s name was called, he spoke up loudly and said, “Robert A. DeLeo votes for Bob DeLeo,” sparking laughter and applause.

Jones, in his remarks, called for a focus on jobs and the economy. “This should be the opening sentence and not the closing paragraph of this session,” he said.

Rather than tax increases to raise needed revenues, the North Reading lawmaker said, the answer is “broadening the base.”

He said Republicans have “constructive ideas and innovative approaches.”

“We must not be afraid of coming into this magnificent chamber and engaging each other in debate,” he said, adding that “while our differences serve to define us, we must not let them divide us.”